1. Field of the Invention
The present invention relates to programmable switching discs of the type utilized in a chronometer for controlling a sequence of operation of a device, and in particular to such a control disc having a magnetic means for releaseably retaining programmed control fingers in a displaced position for actuating a sensing means.
2. Description of the Prior Art
Switching clocks or cycle control timers are widely utilized in switching chronometers which control the operation of a sequence of events in a larger device. Such chronometers sometimes employ a program carrier in the form of a switching or indexing disc to which a plurality of switch riders are connected, the switch riders being displaceable or otherwise programmed for actuating a number of switch means to initiate a particular event in the operational sequence of the controlled device.
Such switching discs with switch riders carried thereon are known in a great variety of different embodiments, but all conventional such switching discs have the general disadvantage that the switch riders are relatively three-dimensionally large and wide. For a switching disc which rotates at one revolution per 24 hours or one revolution per week, it is generally desirable that the switching disc be programmable to initiate events in time divisions of respectively approximately 1 minute per 24 hours or 5 minutes per week. For a switching disc having a diameter of approximately, for example, 60 mm, the wideness of conventional switch riders makes such fineness of time division difficult, if not impossible, and thereby sets a lower limit on the precision of the operating program. The chronological spacing between two successive control instructions is frequently required to lie within the above, heretofore unattainable, values.